JP2008010930A - Frame signal transmitting system - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a frame signal transmitting system capable of easily realizing switching without instantaneous interruption between a plurality of transmitting paths for transmitting frame signals in parallel. <P>SOLUTION: Frame signals of quality classes set for each frame are generated in association with each of a plurality of transmitting paths, and supplied to the transmission path in an order corresponding to the quality classes. Frames of arriving frame signals are classified depending on its quality class for each transmission path, the plurality of frame signals including the classified frames classified for the quality class are subjected to phase matching processing for each of the quality class, systems are switched for each class after phase matching from the plurality of frame signals subjected to the phase matching processing for each quality class in response to a system switching command for each quality class in one transmitting path among the plurality of transmitting paths, and the frame signals classified into the plurality of quality classes selected for each quality class are each read. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  In the present invention, information such as voice, data, video information, etc. is stored continuously in a stream form like a cell in an ATM (Asynchronous Transfer Mode) system or a frame in an EPON (Ethernet (registered trademark) Passive Optical Network) system. The present invention relates to a frame signal transmission system for transmitting a frame signal composed of transmission units (hereinafter, referred to as a frame collectively) generated in this manner.

  There is a PON system as a method for realizing an optical access network for subscribers called FTTH (Fiber To The Home). FIG. 1 shows an outline of a known PON system. The PON system is a system for reducing the cost of an optical access network by accommodating a plurality of subscribers with a single station interface. As shown in FIG. 1, an optical fiber extending from a subscriber terminal device (hereinafter referred to as OLT) which is a station interface is branched by the number of accommodated subscribers in a splitter, and the branched optical fiber is further sent to each subscriber. It is extended and terminated in an optical terminal unit (hereinafter referred to as ONU) in the subscriber's house. A signal from the OLT to each ONU (hereinafter referred to as a downstream signal) and a signal from each ONU to the OLT (hereinafter referred to as an upstream signal) are transmitted at different wavelengths, enabling bidirectional simultaneous communication. Yes.

  As a downlink signal transmission method, there are a time division multiplexing method (TDM method) and a wavelength multiplexing method (WDM method). In the time division multiplexing method, the downstream signal to each ONU is time division multiplexed and broadcasted (broadcast) to each ONU via the splitter, and each ONU extracts and receives only the signal addressed to itself. In the wavelength division multiplexing method, a downstream signal to each ONU is wavelength-multiplexed with a different wavelength for each ONU, and each ONU receives and receives only a wavelength including a signal addressed to itself.

  On the other hand, as an uplink signal transmission method, there are a time division multiplexing method (TDM method) and a wavelength multiplexing method (WDM method). In the time division multiplexing method, the OLT individually instructs each ONU in advance of the transmission timing of the upstream signal, and each ONU transmits the upstream signal in bursts to the OLT at a necessary timing according to this instruction. Other than this transmission timing, each ONU stops signal output. Upstream signals transmitted from each ONU in a burst form merge via a splitter, and are time-division multiplexed and transmitted to the OLT. Here, the transmission timing instructed from the OLT to each ONU is adjusted so that uplink signals from a plurality of ONUs do not collide when they join.

  In recent years, communication based on Ethernet (registered trademark) has become mainstream in Internet communication, and real-time communication such as voice communication using VoIP technology has become common on Ethernet (registered trademark). . Also in the PON system described above, the application of the EPON system for transmitting Ethernet (registered trademark) frame signals is expanding. In real-time communication over Ethernet (registered trademark), quality control for guaranteeing communication quality such as delay characteristics is generally performed. Therefore, a quality control function is also provided in the EPON system.

  FIG. 2 shows an example of the configuration of an EPON system equipped with a quality control function. On the downstream side (from the OLT to the ONU direction), the input frame signal is input to the PON IF unit via the OLT service node interface (hereinafter referred to as SNI). Each input frame signal has a quality class identifier (in this example, n classes represented by integers 1 to n) indicating which quality class the frame signal is. In the PON IF units # 1 to # 3, a plurality of buffers # 1 to #n (hereinafter referred to as QoS buffers) corresponding to each quality class are prepared, and each frame of the input frame signal is provided. Are sorted into QoS buffers corresponding to the white quality class. The output terminal of each QoS buffer is connected to the input terminal of the output buffer, and a frame is read from each QoS buffer and input to the output buffer so as to maintain communication quality corresponding to each quality class. The frames stored in the output buffer are sequentially output via the PON interface and broadcast to each ONU. The communication quality can be ensured by controlling the read operation from the QoS buffer to the output buffer.

  For example, since frames for storing audio signals and video signals are required to have real-time characteristics, as long as there is a frame in the QoS buffer corresponding to the quality class, all frames from the QoS buffer are prioritized over other quality classes. Priority control processing for continuously outputting is performed. As a result, the real-time property of the frame signal transmitted on the Ethernet (registered trademark) is ensured. Similarly, on the upstream side (ONU to OLT direction), a similar quality control function is mounted in each ONU, and similar priority control is performed and output to the OLT.

By the way, when such a PON system has a redundant configuration including a plurality of transmission paths, it is required to selectively switch any of the plurality of transmission paths. As a technique for realizing such switching, there is a technique disclosed in Patent Document 1 entitled “Data Communication System and Data Communication Method”. In this technology, the 0-system OLT and the 1-system OLT having a duplex configuration, and the 0-system ONU and the 1-system ONUs synchronize their internal states with each other, so that the PON in the transmission path is synchronized. It is devised so that the cell transfer order of the ATM cells transmitted in the section completely matches. As a result, on the downstream side of the signal transmitted to the duplexed transmission path, switching without interruption is realized by making the phase difference between the 0 system and the 1 system coincide with each other without regard to the cell transfer order. The
JP 2002-199884 A

  However, in such a technique, it is necessary to match the phases including the cell or frame transmission order of the output signals of the 0-system and the 1-system. Therefore, the internal state of the PON layer processing unit between the two OLTs in the upstream signal processing and the internal state of the PON layer processing unit between the two ONUs in the downstream signal may be shared and matched between the two systems. Has been done. However, when trying to support PON layer processing with a developed LSI, the LSl may not necessarily have a structure that can extract information necessary for synchronization between both systems. There is a problem that uninterruptible switching cannot be realized depending on the restrictions.

  The present invention has been made in view of the above problems, and an object thereof is to provide a frame signal transmission system that can easily realize uninterrupted switching between a plurality of transmission paths for transmitting frame signals in parallel. is there.

  A frame signal transmission system according to the present invention is a frame signal transmission system that transmits a frame signal having a quality class set for each frame in parallel via a plurality of transmission paths, and duplicates the frame signal for each frame. A signal duplicating means for generating a plurality of frame signals corresponding to each of the plurality of transmission paths, and for each transmission path, each frame of the frame signal corresponding to the transmission path in an order corresponding to the quality class. Signal supply means for supplying to the transmission path, signal distribution means for distributing each frame of the frame signal coming from the transmission path for each transmission path according to the quality class, and the quality for each quality class Phase matching means for performing phase matching processing on a plurality of frame signals including frames assigned to classes, and a plurality of transmission paths; Switching means for switching a system for each class after phase matching from among a plurality of frame signals subjected to phase matching processing for each quality class in response to a system switching command for each quality class in one transmission path of Signal reading means for reading each of a plurality of quality class-specific frame signals selected for each quality class.

  According to the frame signal transmission system of the present invention, a configuration is provided in which switching is performed with phase matching for each quality class. Accordingly, it is possible to easily realize non-instantaneous switching of a plurality of transmission paths for transmitting frame signals in parallel.

  Embodiments of the present invention will be described in detail with reference to the accompanying drawings.

  3 and 4 show a configuration of an EPON system which is a first embodiment and is a frame signal transmission system according to the present invention. The EPON system 10 includes a duplexed OLT device 20 and at least one duplexed ONU device 60. Between the duplexed OLT device 20 and the duplexed ONU device 60, a 0-system optical fiber L0 via a splitter 50 that realizes a star configuration. Similarly, it is connected to the 1-system optical fiber L1 via the splitter 51 that realizes a star configuration, and enables bidirectional communication in the downstream and upstream directions. When one of the two systems, the 0 system and the 1 system, is operated as an active system, the other system is set in a standby state as a standby system. The 0-system optical fiber L0 and the 1-system optical fiber L1 constitute a plurality of transmission paths.

  In this figure, one duplexed ONU device 60 is shown, but a duplexed OLT device 20 can be connected to a plurality of duplexed ONU devices in a star configuration via splitters 50 and 51. In this case, the downlink signal is broadcasted by time division multiplexing to each of the plurality of duplexed ONU devices. The upstream signal is collected independently from each of the plurality of duplexed ONU devices to the duplexed OLT device.

  Referring to FIG. 3, the configuration of the EPON system is shown paying attention to the downstream signal flow. The Ethernet (registered trademark) frame signal input from the service node interface (SNI) is input to the copy insertion unit 34 of the OLT redundancy unit 30 included in the duplexed OLT device 20. One signal is input to the 0-system OLT 40 that performs the 0-system PON layer process, and the other signal is input to the 1-system OLT 41 that performs the 1-system PON layer process. Further, the OLT redundancy unit 30 includes a switching frame generation unit 33, and generates a switching frame used for phase adjustment and switching trigger of uninterrupted switching. The switching frame is inserted by the copy insertion unit 34 before the frame signal input from the SNI is duplicated.

  The 0-system OLT 40 includes a plurality of QoS buffers 401 to 40n for each positive number n of quality classes # 1 to #n. Each of the plurality of QoS buffers 401 to 40n corresponds to each of the quality classes # 1 to #n. Each frame constituting the Ethernet (registered trademark) frame signal belongs to one of the quality classes # 1 to #n. For example, when an IP packet is transmitted by a frame signal, a QoS identifier set in a TOS (Type of Service) field in the IP packet can be used as information indicating a quality class.

  Each frame of the frame signal input to the 0-system OLT 40 is input to a corresponding QoS buffer among the plurality of QoS buffers 401 to 40n according to the quality class. Outputs from the plurality of QoS buffers 401 to 40 n are output to the output buffer 400. The output from each of the QoS buffers 401 to 40n to the output buffer 400 is preferentially controlled according to each quality class. For example, as long as there is a frame in a quality class QoS buffer having real-time characteristics such as voice, priority control is performed so that the frame is output from the QoS buffer to the output buffer 400 in preference to other quality classes. The output of the output buffer 400 is subjected to PON layer processing and is output toward the duplexed ONU device 60 as the output of the 0-system OLT 40.

  Similar to the 0-system OLT 40, the 1-system OLT 41 includes a plurality of QoS buffers 411 to 41n for each positive number n of quality classes # 1 to #n. Each of the plurality of QoS buffers 411 to 41n corresponds to each of the quality classes # 1 to #n. Each frame of the frame signal input to the 1-system OLT 41 is input to a corresponding QoS buffer among the plurality of QoS buffers 411 to 41n according to the quality class. Outputs from the plurality of QoS buffers 411 to 41n are output to the output buffer 410. The output from each of the QoS buffers 411 to 40n to the output buffer 400 is preferentially controlled according to each quality class. The output of the output buffer 410 is subjected to PON layer processing and is output toward the duplexed ONU device 60 as the output of the 1-system OLT 41.

  The frame signal output from the 0-system OLT 40 toward the duplexed ONU device 60 is input to the 0-system ONU 70 of the duplexed ONU device 60 via the optical fiber configured in a star shape by the splitter 50. The 0-system ONU 70 identifies and fetches the frame signal addressed to itself among the input frame signals from the ONU number defined in the inside of the frame, performs PON layer processing on the frame signal, and outputs this 0 It outputs to ONU redundancy part 80 as a system frame signal. Similarly, the frame signal output from the 1-system OLT 41 toward the duplexed ONU apparatus 60 is input to the 1-system ONU 71 of the duplexed ONU apparatus 60 via the optical fiber configured in a star shape by the splitter 51. The 1-system ONU 71 identifies and fetches the frame signal addressed to itself among the input frame signals from the ONU number defined in the frame, performs PON layer processing on the frame signal, It outputs to ONU redundancy part 80 as a system frame signal.

  The 0-system frame signal and the 1-system frame signal input to the ONU redundancy section 80 include a plurality of quality classes # 1 to ## provided in the ONU redundancy section 80 according to the quality class indicated in the frame. The n phase matching units 811 to 81n corresponding to n are input to the 0-system input terminal and the 1-system input terminal, respectively.

  The 0 system output and 1 system output of each of the n phase matching units 811 to 81n are the 0 system input terminal and 1 system input of the n selectors 821 to 82n corresponding to the n phase matching units 811 to 81n, respectively. Each is input to the end. Each of the n selectors 821 to 82n selectively switches between a 0-system frame signal and a 1-system frame signal in response to a system switching command designating either the 0-system or the 1-system, and the selected frame The signal is output to the buffer 800. This switching is performed for each quality class. As for the switching timing of each quality class, when the system switching command is issued by the switching frame after the phase matching process is completed, the system is switched from the next frame of the switching frame. This process is performed for each quality class. Thereby, when it sees by the quality class unit, it can switch to uninterrupted without the frame overlapping or missing. The buffer output of each quality class after system switching is output to the output buffer by reading control according to the quality class. The output of the output buffer 800 is externally output via a user network interface (UNI).

Referring to FIG. 4, the configuration of the EPON system is shown focusing on the flow of upstream signals.
The Ethernet (registered trademark) frame signal input from the user network interface (UNI) is input to the copy insertion unit 84 of the ONU redundancy unit 80 included in the duplexed ONU device 60. One signal is input to the 0-system ONU 70 that performs the 0-system PON layer processing, and the other signal is input to the 1-system ONU 71 that performs the 1-system PON layer processing. Further, the ONU redundancy unit 80 has a switching frame generation unit 83, and generates a switching frame used for phase adjustment and switching trigger of uninterrupted switching. The switching frame is inserted by the copy inserting unit 84 before the frame signal input from the UNI is copied.

  The 0-system ONU 70 includes a plurality of QoS buffers 701 to 70n for each of n quality classes. Each of the plurality of QoS buffers 701 to 70n corresponds to each of n quality classes # 1 to #n. Each frame of the frame signal input to the 0-system ONU 70 is input to a corresponding QoS buffer among the plurality of QoS buffers 701 to 70n according to the quality class. Outputs from the plurality of QoS buffers 701 to 70n are output to the output buffer 700. The output of the output buffer 700 is subjected to PON layer processing and output to the duplexed OLT device 20 as an output of the 0-system ONU 70. .

  Similar to the 0-system ONU 70, the 1-system ONU 71 includes a plurality of QoS buffers 711 to 71n for each of n quality classes. Each of the plurality of QoS buffers 711 to 71n corresponds to each of n quality classes # 1 to #n. Each frame of the frame signal input to the 1-system ONU 71 is input to a corresponding QoS buffer among the plurality of QoS buffers 711 to 71n according to the quality class. The outputs from the plurality of QoS buffers 711 to 71n are output to the output buffer 710, and the output of the output buffer 710 is subjected to the PON layer processing and output to the duplexed OLT device 20 as the output of the 1-system ONU 71. .

  The frame signal output from the 0-system ONU 70 toward the duplexed OLT device 20 is input to the 0-system OOLT 40 of the duplexed OLT device 20 via the optical fiber configured in a star shape by the splitter 50. The 0-system OLT 40 performs PON layer processing on the frame signal, and outputs this to the OLT redundancy unit 30 as a 0-system frame signal. Similarly, the frame signal output from the 1-system ONU 71 toward the duplex OLT apparatus 20 is input to the 1-system OLT 41 of the duplex OLT apparatus 20 via the optical fiber configured in a star shape by the splitter 51. The 1-system OLT 41 performs PON layer processing on the frame signal, and outputs this to the OLT redundancy unit 30 as a 1-system frame signal.

  The 0-system frame signal and the 1-system frame signal input to the ONU redundancy unit 30 are n phase matching units 311 to 31n corresponding to a plurality of quality classes # 1 to #n included in the OLT redundancy unit 30. Are respectively input to the 0-system input terminal and the 1-system input terminal. The 0 system output and 1 system output of each of the n phase matching units 311 to 31n are the 0 system input terminal and 1 system input of the n selectors 321 to 32n corresponding to the n phase matching units 311 to 31n, respectively. Each is input to the end. Each of the n selectors 321 to 32n selectively switches between the 0-system frame signal and the 1-system frame signal in response to a system switching command designating either the 0 system or the 1 system, and the selected frame The signal is output to the buffer 300. This switching is performed for each quality class. As for the switching timing of each quality class, when the system switching command is issued by the switching frame after the phase matching process is completed, the system is switched from the next frame of the switching frame. This process is performed for each quality class. Thereby, when it sees by the quality class unit, it can switch to uninterrupted without the frame overlapping or missing. The buffer output of each quality class after system switching is output to the output buffer by reading control according to the quality class. The output of the output buffer 300 is externally output via a system node interface (SNI).

  FIG. 5 illustrates the phase matching executed by the phase matching unit. In this figure, the horizontal axis takes time, the state (a) where the 0-system frame signal and the 1-system frame signal are not phase-matched, and the state where the 0-system frame signal and the 1-system frame signal are phase-matched (B) and FIG. In each of the 0-system frame signal and the 1-system frame signal, as shown in the figure, Ethernet (registered trademark) frames are consecutive in the order of their sequence numbers.

  In the state where phase matching is not performed in (a), there is a phase difference between the 0-system frame signal and the 1-system frame signal. For this reason, if the entire frame flow of each of the 0-system and the 1-system is switched at once, a frame loss occurs and an instantaneous interruption occurs. Therefore, a phase matching process is performed at the same timing as the delayed signal by delaying the signal of the advanced system.

  In the phase matching state of (b), there is no phase difference between the 0-system frame signal and the 1-system frame signal. Therefore, will not instantaneous interruption occurs be switched at any timing because the phase match. Although switching is possible at any timing after phase matching, it is preferable to switch at the switching frame as the system switching timing for safety. As described above, a switching frame is inserted into each of the 0-system frame signal and the 1-system frame signal.

  The switching frame is generated independently for each quality class at a predetermined cycle by the switching frame generator 33 or 83 (see FIGS. 3 and 4). Since the switching frame is inserted before the copying process for obtaining the frame signals of both systems, it flows in both the 0 system and the 1 system. Further, as a result of the priority control according to each quality class, the frame transfer order of both systems, that is, the order including the switching frame, is completely the same for one quality class. Therefore, the systems can be switched individually when the phases of both systems coincide in the phase matching section of each quality class. In all quality classes, when the system is switched, the system switching is completely completed, and the system that is the standby system as it is now becomes the new working system.

  FIG. 6 shows an example of the configuration of the switching frame. The illustrated frame 90 is an EtherOAM common frame format recommended by ITU-T. Here, by defining identification information indicating “switching frame” in the Ether Type field 91, it can be used as a switching frame.

  In the first embodiment described above, the frame signal transmission system according to the present invention sends the same signal to both the 0-system and the 1-system on the transmission side, and receives the 0-system and 1-system signals on the reception side. The sending end parallel method is used. In the transmitting end parallel method, switching operation is realized by switching the system on the receiving side at the time of switching. At the time of switching, the phase matching unit in this embodiment adjusts the phase of each of the 0-system and 1-system signals on the receiving side and switches the system when the phase is negative, for example, delays the signal of the advanced system Phase matching processing is performed to make the signal at the same timing as the delayed signal. With this processing, no instantaneous interruption occurs at any timing, and non-instantaneous switching is realized. The frame signal transmission system according to the present invention is a result of priority control performed in accordance with the quality class by performing non-instantaneous switching for each quality class, which is a unit in which the frame transfer order is guaranteed when performing quality control. As a result, the problem that the coincidence of the frame transfer order in both systems is not guaranteed is avoided.

As described above, by using the frame signal transmission system according to the present invention, it is possible to perform non-instantaneous switching in a redundant configuration without depending on the type of LSI that performs PON layer processing. In addition, it is possible to perform non-instantaneous switching in a redundant configuration without depending on the processing method of the PON layer.
<Second embodiment>
7 and 8 show a configuration of an EPON system which is a second embodiment and is a frame signal transmission system according to the present invention. Referring to FIG. 7, the configuration of an EPON system that is a frame signal transmission system according to the present invention is shown by focusing on the flow of downstream signals. Referring to FIG. 8, the configuration of an EPON system that is a frame signal transmission system according to the present invention. Is shown paying attention to the flow of the upstream signal. In the second embodiment, when it is desired to add a redundancy function after the introduction of a single system without an existing redundancy function, a new redundant system can be easily reused by reusing the existing single system. Provide the form to be realized.

  The EPON system 10 'includes one OLT redundancy device 30', an OLT device 20 ', an ONU device 60', and an ONU redundancy device 80 '. The OLT device 20 ′ and the ONU device 60 ′ are connected to a 0-system optical fiber via a splitter 50 that realizes a star configuration and a 1-system optical fiber via a splitter 51 that also realizes a star configuration. Thus, it is possible to perform downlink and uplink bidirectional communication in each of the 0-system and 1-system optical fibers. The OLT device 20 ′ includes a 0-system OLT 40 and a 1-system OLT 41 that are existing single-layer OLT devices. The ONU device 60 ′ is configured by a 0-system ONU 70 and a 1-system ONU 71 which are existing single ONU devices.

  Although one ONU device 60 ′ is shown in the drawing, a plurality of ONU devices can be connected to the OLT device 20 ′ via a single transmission path in a star configuration via the splitters 50 and 51. In this case, the downlink signal is a signal that is optically transmitted by time-division multiplexing frame signals directed to each of the plurality of duplexed ONU devices. On the other hand, the uplink signal is a signal that is optically transmitted from each of the plurality of duplexed ONU devices.

  The OLT redundancy device 30 ′ has the same configuration as the OLT redundancy unit 30 in the first embodiment, and the ONU redundancy device 80 ′ has the same configuration as the ONU redundancy unit 80 in the first embodiment. Provided (see FIGS. 3 and 4). Therefore, the operation in the second embodiment is performed in the same manner as the operation in the first embodiment, and uninterruptible switching is realized.

In the second embodiment described above, by using the frame signal transmission system according to the present invention, the single OLT and the single ONU having no redundant configuration function can be reused even when the redundant configuration is adopted. Can reduce unnecessary investment of equipment. Such an embodiment is easier to implement than the embodiment in the first embodiment, in which it is necessary to design an apparatus in consideration of a redundant configuration in advance.
<Modification>
FIG. 9 shows a modification of the second embodiment. The EPON system 10 ″ includes one OLT redundancy device 30 ′, OLT devices 20 ′ and 20 ″ connected thereto, 0 system ONU device 70 and 1 system ONU device 71, and ONU redundancy connected thereto. And the conversion device 80 '. Between the OLT device 20 ′ and the 0-system ONU device 70, a 0-system optical fiber via a splitter 50 that realizes a star configuration and a 1-system optical fiber that similarly uses a splitter 51 that realizes a star configuration are connected. Thus, it is possible to perform downlink and uplink bidirectional communication in each of the 0-system and 1-system optical fibers. Each of the OLT devices 20 ′ and 20 ″ includes a plurality of PONIFs # 1 to # 3 each having a function similar to that of the 0-system or 1-system OLT (see FIGS. 3 and 4) described in the first embodiment. Including.

  In this embodiment, a redundant configuration on the OLT side is provided across two OLT devices. Thus, by applying the present invention, a redundant configuration can be established between different OLTs, so that the system can be used more flexibly and efficiently. Furthermore, since the transmission path of another OLT can be changed to another OLT, a flexible network configuration can be built and the accommodation rate can be increased.

  In the above embodiments, the present invention is applied to the EPON system. However, the frame signal transmission system according to the present invention replaces a frame with a cell, and performs priority control according to a quality class. It can also be applied to PON systems.

It is a block diagram which shows the outline | summary of a well-known PON system. It is a block diagram which shows the structural example of the conventional EPON system which mounts a quality control function. 1 is a block diagram showing a configuration of an EPON system which is a first embodiment and is a frame signal transmission system according to the present invention, paying attention to a flow of a downstream signal. FIG. 1 is a block diagram illustrating a configuration of an EPON system that is a first embodiment and is a frame signal transmission system according to the present invention, focusing on the flow of an upstream signal. FIG. It is explanatory drawing explaining the mode of the phase matching performed by a phase matching part. It is a figure which shows the structural example of a switching | prevention | shift fulm. It is a block diagram which shows the structure of the EPON system which is a 2nd Example and is a frame signal transmission system by this invention paying attention to the flow of a downstream signal. It is a block diagram which shows the structure of the EPON system which is a 2nd Example and is a frame signal transmission system by this invention paying attention to the flow of an upstream signal. It is a block diagram which shows the modification of a 2nd Example.

Explanation of symbols

10, 10 ', 10 "PON system 20 Duplex OLT device 30 OLT redundancy unit 30' OLT redundancy device 33 Switch frame generation unit 34 Copy insertion unit 40 0 system OLT
41 Series 1 OLT
50, 51 Splitter 60 Duplex ONU device 70 Series 0 ONU
71 1 system ONU
80 ONU redundancy unit 80 'ONU redundancy unit 83 switching frame generation unit 84 copy insertion unit 300 output buffer 311 to 31n phase matching unit 321 to 32n selector 400 output buffer 401 to 40n QoS buffer 410 output buffer 411 to 41n QoS buffer 700 Output buffer 701 to 70n QoS buffer 710 Output buffer 711 to 71n QoS buffer 800 Output buffer 811 to 81n Phase matching unit 821 to 82n Selector L0 0 system optical fiber L1 1 system optical fiber

Claims (5)

A frame signal transmission system for transmitting a frame signal in which a quality class is set for each frame in parallel via a plurality of transmission paths,
Signal duplicating means for duplicating the frame signal for each frame to generate a plurality of frame signals corresponding to each of the plurality of transmission paths;
For each transmission path, signal supply means for supplying each frame of the frame signal corresponding to the transmission path to the transmission path in an order according to the quality class;
For each transmission path, signal distribution means for distributing each frame of the frame signal coming from the transmission path according to its quality class;
Phase matching means for performing phase matching on a plurality of frame signals including frames allocated to the quality class for each quality class;
In response to a system switching command for each quality class in one transmission path among the plurality of transmission paths, for each class after phase matching from among a plurality of frame signals subjected to phase matching processing for each quality class System switching means for switching the system;
Signal reading means for reading each of the plurality of quality class-specific frame signals selected for each of the quality classes;
A frame signal transmission system comprising:   The signal duplicating means inserts a switching frame into the frame signal for each quality class prior to duplicating the frame signal, and the system switching means performs the quality in response to detection of the switching frame for each quality class. 2. The frame signal transmission system according to claim 1, wherein an operation of selecting a frame signal corresponding to the one transmission path for each class is performed for each quality class.   The signal supply means distributes and accumulates each frame of the frame signal corresponding to the transmission path to one of a plurality of quality class buffers according to the quality class, and accumulates from the switched quality class buffer. 2. The frame signal transmission system according to claim 1, wherein the frames are continuously read out and supplied to the transmission path.   An EPON network including the plurality of transmission paths; an OLT redundancy apparatus including the signal duplicating means; a multiplexed OLT apparatus including the signal supplying means and performing a PON layer process; and a PON layer including the signal distributing means 2. The frame signal transmission system according to claim 1, comprising at least one multiplexed ONU device for processing and at least one ONU redundancy device including the phase matching means and the system switching means.   An EPON network including the plurality of transmission paths; at least one ONU redundancy device including the signal duplication unit; at least one multiplexed ONU device including the signal supply unit and performing PON layer processing; and the signal distribution 2. The frame signal transmission system according to claim 1, further comprising: a multiplexed OLT device including a means and performing a PON layer process; and an OLT redundancy device including the phase matching means and the system switching means.

Images